Automatic circuit breaker reclosing mechanism



Nov. 10, 1936. G D, GAMEL 2,060,494

AUTOMATIC CIRCUIT BREAKER RECLOSING MECHANISM Filed NOV. 13, 1954 i I m -J fig ijfib 280 26 28m /24 26 2s 3 /st. Reset P05227022 INVENTOR Gayne 2 Game].

WITNESSES Patented Nov. 10, 1936 UNITED STATES AUTOMATIC 013cm BREAKER ancnosmc MECHANISM Gayne D. Game], Pittsburgh, Pa., assignor ,to

Westinghouse Electric 8: Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 13, 1934; Serial No. 752,815 I 15 Claims. (Cl. 115-294) My invention relates, generally, to electrical control systems, and it has particular relation to systems for automatically reclosing circuit breakers. v

The object of my invention, generally stated, is to provide a reclosing system for circuit breake-rs which will be simple and efiicient in operation, and which may be readily and economically manufactured and installed.

The principal object of my invention is to provide for automatically reclosing a circuit breaker.

A more speciflcobject of my invention is to provide for effecting a predetermined number 'of timed reclosures of a circuit interrupter in response to successive openings thereof by means of a thermal switching device.

An important object of my invention is to provide for locking out a reclosing system to prevent reclosure of a circuit breaker after it has been reclosed a predetermined number of times.

A further object of my invention is to provide for automatically resetting a reclosing system for circuit breakers when'the circuit breaker remains in the closed position.

A still further object of my invention is to provide for effecting either a single reclosure or a plurality of reclosures of a circuit breaker, and for restoring the reclosing system therefor to its initial non-operating condition when the circuit breaker remains in the closed position.

Other objects of my invention will, in part, be obvious and, in part, appear hereinafter.

My invention, accordingly, is disclosed in the embodiment hereof shown in the accompanying drawing and comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of my invention, reference may be had to the following detailed description, taken in connection with the accompanying drawing,

in which:

Figure 1 illustrates diagrammatic-ally a concrete embodiment of my invention; and

Figs. 2 through 6 illustrate different positions of the thermal elements which are employed in practicing my invention.

When a circuit breaker which is used to connect two sections of an electric power system together is automatically tripped out, due to a fault, it is often desirable to immediately effect its reclosure.

of the met that the fault may be of a momensome instances, however, it is desirable to resented by conductorsi i and i2. of illustration, the power system is illustrated as Such operation is desirable in view tary nature and may be immediately cleared as soon as the circuit breaker is opened. In

close. the circuit breaker for more than one time, such, for example, as a predetermined number of times at predetermined intervals, in order to effect the clearing of the fault, or to maintain stability in the system.

In order'to effect the reclosing of the circuit breaker, I have provided a thermal switching device comprising a plurality of sequentially operable thermal devices. -As soon as the circuit breaker is tripped; an energizing circuit is completed through the first of the thermal devices for effecting an immediate reclosure of the circuit breaker. The heating element of the thermal device is energized in response to the opening of the breaker, which, after an interval of time causes the thermal element to open the operating circuit, and at the same time, effect-' ingthe deenergization of the heating element. If the-circuit breaker reopens immediately, the heating element is again energized or remains energized and continues to heat or reheats the thermal element until it is effective to again complete' the energizing circuit, whereupon the circuit breaker is again closed.

The foregoing cycle of operations continues until all of the thermal devices have been effec tive, or until the circuit breaker remains in the closed position. If the circuit breaker trips out after the last thermal device has operated, no further operation can take place, since the reclosing system is automatically locked out at this point.

Referring now particularly to Fig. l of the drawing, the reference character l0 designates a circuit breaker which is disposed to connect two sections of a power system which may be'repre- For the purposes being an alternating-current power system, but it will be readily understood that this invention may be also used in connection with a directcurrent power system. v

l'he circuit breaker ill is provided with a trip winding l3 which is associated with an armature IL The winding I3 is connected for energization toa secondary winding 15 of a current transformer, the primary winding of which comprises one of the conductors it It will be readily understood that a suitable relay may be interposed between the secondary winding i5 and the ratus is desired or that the circuit breaker may be tripped in response to any other circuit condition.

In order to operate the circuit breaker I0 to the closed position, an operating mechanism is provided therefor which comprises a closing winding I8 that is associated with an armature II. The operating means also comprises an auxiliary relay, shown generally at It, having an operating winding llw and contact members Ila and Ilb, the function of which will be set forth hereinafter. The circuit breaker iii is also provided with an' auxiliary switch IS, the contact members of which are bridged when the circuit breaker is in the open position. The contact members of the auxiliary switch I9 are connected in parallel circuit relation with contact members Ila oi the auxiliary relay I8 for a purpose which will also be set forth hereinafter.

In order to manually control the operation of the circuit breaker III, a control switch shown generally at 20, is provided, having contact members 20a which are disposed to connect the operating mechanism for energization to a control source, which may be represented by conductors 2i and 22.

In order to eflect the automatic reclosing o! the circuit breaker I0 in the event that it is tripped on energization of the trip winding I3, a plurality of sequentially-operable thermal devices are provided. The thermal devices comprise bimetallic strips or thermal elements 24, 26, and 28, respectively. It will be understood that the thermal elements 24, 28, and 24 are constructed of dissimilar metals having difierent thermal coefficients of expansion, so that they may be deflected on the application of heat thereto.

As illustrated, each or the thermal elements 24, 26, and 28 has associated therewith respectively a heating element 24):, 25h, and 24h. In addition, the thermal element 24 has associated therewith a contact member 24a which is normally in engagement therewith. Thermal element 28 has a contact member 28a with which it is normally in engagement, and a contact member 26b, which is normally out of engagement therewith, but which may be moved into engagement therewith by means of the thermal element 24. The thermal element 28 has associated with it fixed contact members 28a and 28c, and a contact member 28b which is movable therewith.

In the event that it is desired to only provide for a single reclosure of the circuit breaker II) when it has been automatically tripped, the thermal element 24 and associated heating element 24h, and contact member 24a need only be used. However, it it is desired to reclose the circuit breaker I0 more than a single time, then the additional thermal devices are required, the number corresponding to the number of times that it is desired to reclose the circuit breaker III.

In operation, the switch 20 is closed to eilect the operation of the auxiliary relay II which, in

' turn, completes a circuit for energizing the closing winding It. The circuit breaker Ill is then operated to the closed position connecting the conductors II to the conductors I2 in the usual manner.

The circuit for energizing the operating wind ing law may be traced from the energized conductor 2! through conductor '30, contact members 200, conductor 3i, operating winding Ilw, con ductor 32, contact member 24a, thermal element 24, conductor 33,'the contact members of aux- 1 9,060,494 trip winding II it such an arrangement of apps.-

iliary switch I! and conductors l4 and 4| to the energized conductor 22.

At contact members Ilb, an obvious energizing circuit for the closing winding I4 is completed. At contact members Ila, the contact members oi the auxiliary switch I! are shunted, thereby maintaining intact the energizing circuit for the operating winding llw, after the contact members of the. auxiliary switch II are opened, on closure of the circuit breaker ll.

As long as the thermal element 24 remains in contact engagement with the contact member 24a, the energizing circuit for the operating winding llw will be maintained. At the same time that the operating winding Ilw is energized, it will be observed that the heating element 24h is also energized. The temperature of the thermal element 24 is then increased as a result of the heat generated by the heating element 2471, which causes it to deflect to a position which may be termed the first reset position as is illustrated in Fig. 2 of the drawing. It will be understood that the energizing circuit for the operating winding law is then opened, since the thermal element 24 no longer remains in contact engagement with the contact member 24a.

The circuit for energizing the heating element 24h may be traced from the energized conductor 2I through conductor 30, contact members 20a, conductors 3i and 26, heating element 24h, conductor 23, contact members Ila, and conductors 34 and 35 to the energized conductor 22.

The opening of the energizing circuit for the operating winding Ilw oi the auxiliary relay II causes it to be restored to the normal position. and at contact members Ila the energizing circuit for the heating element 24his opened. It is deenergized and no longer applies heat to the thermal element 24. It the circuit breaker it remains in the closed position, the thermal element 24 will be restored to the normal position shown in Fig. 1.

Assuming, however, that only a single thermal element 24 is provided, and that the circuit breaker I0 immediately trips out as soon as it has been closed, it will be observed that the heating elemeht 24h will be immediately reenergized through the contact members 01' the auxiliary switch I9, and will continue to apply heat to the thermal element 24. Since the thermal element 24 will not, as yet, have been restored to the normal position, it will not be possible to complete the energizing circuit for the operating winding i810, and as a result, the circuit breaker I0 cannot beagain reclosed until the system is manually reset.

However, it the additional thermal elements 24 and 28 are'provided, as illustrated, the circuit breaker in may be reclosed two more times. Assuming that the circuit breaker I0 is automatically tripped again, the heating element 24):. will be reenergized by the closing oi the contact members of the auxiliary switch I! and the thermal element 24 will be deflected to engage the contact member 26b and to move it into engagement with the thermal element 24. The relative positions of the thermal elements and contact membera as thus described, are illustrated in Fig. 3 or the drawing. Circuits are now completed for energizing the operating winding IIlw to ei'lect the second reclosure oi circuit breaker II and for energizing the heating element 2611 to increase the temperature oi the thermal element 24.

The circuit for energizing the operating winding ilw may now be traced from the energized conductor 2i through conductor 30, contact members 20a, conductor 3|, operating winding 18w, conductor 31, contact member 28a, thermal element 26, contact member 26b, thermal element- 24, conductor 33, contact members of the auxiliary switch l9 andconductors34 and 35 to the energized conductor 22. The circuit for energizing the heating element 26h may be. tracedfrom the energized conductor 2| through conductor 30,

contact members a, conductors SI and 38, heating element 26k, to the contact member 261) andthence over the circuitwhich has just been traced for energizing the operating winding l8w.

'It will now'be observed that both heating elements 24h and 26h are energized in order to maintain the thermal elements 24 and 2B in a heated condition. The continued heatingv of the thermal element 26 causes it to open the energizing circuit for the operating winding law, which had' been bridged between contact members 26a and .261) by the thermal element 26. This condition is illustrated in Fig. 4 of the drawing, in what may be termed a second reset position. The operating winding l8'w is then'deenergized and at contact members la the energizing circuits for the heating elements 247:. and 26h are opened, thereby permitting the thermal elements 24 and 26 to be restored to their normal positions, as illustrated in Fig. lot the drawing. I

In the event that the circuit breaker Hi again immediately trips 'out, it will be observed that the energizing circuits for the heating elements 24h and 267; will be completed at the contact members of the auxiliary switch 19. Since the thermal elements 24 and 26 have not, as yet, been restored to their normal positions, they will continue to be heated and finally the thermal element 26 will assume the position illustrated in Fig, 5 in order to efiect the third reciosure of the circuit breaker iii. .In this position, the thermal element 26 bridges the contact members 23a, 28b,

.and 280, in orderto again eifect the energization of the operating winding l8w and to energize the heating element 2871.

The circuit for nowenergizing the operating winding i8w may be traced from the-energized conductor 2| through conductor 30, contact members 20a, conductor. 3!, operating winding l8w,.

conductors 31, 32, and 39, thermal element 28, contact members 28b and 28a bridged by the thermalelement 2.6, conductors 40 and 33, contact members of the auxiliary switch l9 and conductors 34 and to the energized conductor 22. The circuit for energizing the heating element 28h' may be traced from the energized conductor 2| through conductor 30, contact members 20a, conductors 3i and 4|, heating element 28h, contact member 280, and thence through thermal element 26 and contact member 28a over the same circuit which has just been traced for energizing .the operating winding I810.

The energization of the heating element 2871 increases the temperature of the thermal element 2B and causes it to move towhat may be termed the lock-out position, which is illustrated in Fig. 6 of the drawing. When the thermal element 28 is operated to the position there shown, the energizing circuit for the operating winding Him is opened, and the auxiliary relay I8 is restored to its normal position.

In the event that the circuit breaker I0 is immediately tripped out, the heating elements 24h,

' 26h, and'28h will be reenergized and will be effecin Fig. 6 or the drawing. It will then be necessaryto manually reset the system. This may be accomplished by operating the switch 20 to the open position, thereby deenergizing all of' the heating elements and restoring the system to the condition illustrated in Fig. 1 of the drawing.

' Although three thermal elements 24, 26, and 28 have been illustrated, it will be readily under stood that a greater or a lesser number may be employed, without departing from the scope of this invention. Since certain further changes may be made in the foregoing construction, and different embodiments of the invention may be made without departing from the spirit thereof, it is intended that all matter shown in the accompanying drawing or described in the foregoing specification shall be interpreted as illustrative and not in a limiting sense. I claim as my invention:

1. A reclosing system for a circuit breaker provided with operating means comprising, in combination, a thermal device having a normal and an,'operated position, means responsive to the said operating means for reclosing the circuit breaker, and means for maintaining said thermal device in the operated position on the immediate reopening of the circuit breaker.

2. A reclosing system for a circuit breaker provided with operating means comprising, in combination, a thermal device, means for effecting the energization of said thermal device and the operating means through said thermal device thereby in turn deenergizing the operating means, and means responsive to the immediate opening of' the circuit breaker. for continuing the energization of said thermal device to effect the reclo sure of the circuitbreaker.

3. A reclosing system for a circuit breaker pro-' vided with operating means comprising, incombination, a thermal device having a normal and an operated position, means for effecting the energization of said thermal device and the operating means through said thermal device thereby permitting said thermal device to reset when the circuit breaker remains in the closed position.

4. A reclosing system for a circuit breaker provided with operating means and an auxiliary switch comprising, in combination, a thermal device disposed to complete an energizing circuit through the auxiliary switch for the operating means when'the circuit breaker is in the open position, and a heating element d sposed in operative relation'to said thermal device .for energiz ing it to open the circuit to the operating means subsequent to the energization of the operating means. i

5. A reclosing system for a circuit breaker provided with operating means and an auxiliary switch comprising, in combination, a thermal device disposed to complete an energizing circuit through the auxiliary switch for the operating means when the circuit breaker is in the open position, and a heating element connected to be energized on opening of the circuit breaker and disposed in operative relation to said thermal device for heating it to open the circuit to the operating means andto' maintain said thermal device energized on the immediate reopening of the circuit breaker.

6. A reclosing system for a circuit breaker comprising a plurality of sequentially-operable thermal devices disposed to successively efiect the reclosure oi the circuit breaker a predetermined number of times, and means for efiecting the sequential operation of said thermal devices in response to the successive automatic opening of the circuit breaker.

7. A reclosing system for a circuit breaker provided with operating means comprising, in combination, a plurality oi sequentially operable thermal devices, and means responsive to the opening of the circuit breaker for initiating the functioning of said thermal devices for successively eirecting the energization of the operating means in response to the successive automatic opening of the circuit breaker.

8. A reclosing system for a circuit breaker provided with operating means comprising, in combination, a plurality of sequentially-operable thermal devices,.means responsive to the opening of the circuit breaker for initiating the functioning of said thermal devices for successively effecting the energization of the operating means in response to the successive automatic opening of the circuit breaker, and means for preventing further energizatiorn oi the operating means after the circuit breaker has been closed a predetermined number of times and is then opened.

9. A reclosing system for a circuit breaker provided with operating means comprising, in combination, a plurality oi sequentially-operable thermal devices, and meansior sequentially eiiecting the energization of said thermal devices and the operating means through said thermal devices thereby in turn deenergizing and energiaing the operating means for a predetermined number of times in response to the successive opening of the circuit breaker.

10. A reclosing system for a circuit breaker provided with operating means comprising, in combination, a plurality of sequentially-operable thermal devices, means for sequentially eflecting the energization of said thermal devices and the operating means through said thermal devices thereby in turn deenergizing and energizing the operating means for a predetermined number of times in response to the successive opening or the circuit breaker. and means for maintaining the last operated thermal device in the operated position on the immediate reopening oi the circuit breaker and permitting said thermal devices to reset when the circuit breaker remains in the closed position.

11. A reclosing system for a circuit breaker provided with operating means and an auxiliary switch comprising, in combination, a plurality of sequentially-operable thermal devices each disposed to complete an energizing circuit through the auxiliary switch for the operating means when thecircuit breaker is in the open position. and a heating element disposed in operative relation toeach of said thermal devicesfor heating them to open the circuit to the operating means subsequent to the energization of the operating means.

' 12. A reclosing system for a circuit breaker provided with operating means and an auxiliary position, and a heating element disposed in operative relation to each of said thermal devices and connected to be successively energized on successive opening of the circuit breaker for heating said thermal devices to open their respective circuits to the operating means and to maintain said thermal devices energized on the immediate reopening of the circuit breaker.

13. A reclosing system for a circuit breaker provided with operating means comprising, in combination, a plurality of sequentially-operable thermal devices disposed to be successively energized, means for efiecting the sequential operation of said thermal devices on successive opening of the circuit breaker for effecting the energization of the operating means to reclose the circuit breaker, and means for preventing i'urther operation of the circuit breaker after it has been reclosed a predetermined number of times.

14. A reclosing system for a circuit breaker provided with operating means and an auxiliary switch comprising, in combination, a plurality of sequentially-operable thermal devices, the first of said devices being provided with normally closed contact members and the remainder with normally open contact members, said contact members being connected in parallel circuit relation and in series circuit with the operating means and auxiliary switch, and a heating element individual to each thermal device, said circuit breaker on opening completing an energizing circuit for the operating means and heating element of the first thermal device through the auxiliary switch, thereby efiecting a reclosure oi the circuit breaker and energization of the first thermal device to open the energizing circuit tor the operating means, successive opening of the circuit breaker causing the successive energization of the remaining thermal devices to efiect the reclosure oi the circuit breaker for a number of times corresponding to the number of thermal elements.

15. A reclosing system for a circuit breaker provided with operating means comprising, in combination, a thermal device having a normal and an operated position, means responsive to the opening 0! the circuit breaker for initiating the movement of said thermal device to said on erated position and for energizing said operating means to reclose the circuit breaker before said thermal device leaves said normal position, and means for maintaining said thermal device in the operated position on the immediate reopening 0! the circuit breaker to prevent a second immediate reclosure thereof by the same means whereby the first reclosure was efiected.

- GAYNE D. GAMIL. 

